Method and arrangement for feeding chemicals into a process stream

ABSTRACT

An apparatus for feeding one or more chemicals into a process stream of a papermaking process is disclosed, as well as a method of utilizing the apparatus for feeding one or more chemicals into a process stream is disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. Ser. No. 11/339,169filed on Jan. 25, 2006, issued as U.S. Pat. No. 7,550,060 which isherein incorporated by reference.

FIELD OF THE INVENTION

This disclosure relates to a method and apparatus for feeding chemicalsinto a process stream of a papermaking process.

BACKGROUND

Various types and amounts of chemicals are added to a papermakingprocess. In particular, chemicals are added into a process stream of apapermaking process. The optimal feeding of these chemicals is both aquality and a cost issue in that the optimal feeding of chemicals into aprocess stream results in the following: a) better runnability of thepaper machine; b) the quantity of the end product is more predictableand uniform; c) less web breaks and down-time of the paper machine; d) areduction in the quantity of the chemical that needs to feed into apapermaking machine; e) smaller consumption of fresh water; and f) lessenergy is needed to heat fresh water.

Optimal feeding of chemicals into a process stream occurs when there israpid mixing of chemical into the process stream, presence of locallystoichiometric conditions, minimized water usage in the feedingarrangement, and optimal residence/contact times of chemicals. Morespecifically, having locally stoichiometric conditions means having theoptimal ratio of chemicals in the process stream for the chemicals toreact, and optimal residence time of the chemicals means that thechemicals should be fed into the process stream so that all thechemicals that have been fed into the system have had enough time totake effect but not too long to maintain the desired effect.

Many prior art methods and apparatuses for feeding chemicals into aprocess stream of a papermaking process do not result in the optimalfeeding of chemicals into the process stream of a papermaking process.Therefore, a need for an apparatus and method that can optimally feedone or more chemicals into a process stream exists in the papermakingindustry.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for feeding one or morechemicals into a process stream of a papermaking process comprising: afirst conduit having one or more inlets and outlets; a second conduithaving one or more inlets and outlets, wherein said first conduitsecures to said second conduit and traverses said second conduit; amixing chamber that has one or more inlets and outlets, wherein saidsecond conduit secures to said mixing chamber and wherein said outletsof said first conduit and said outlets of said second conduit are incommunication with said mixing chamber; and optionally an adaptor thatis in communication with said outlets of said mixing chamber and issecured to said mixing chamber.

The present invention also provides for a method for feeding one or morechemicals into a process stream of papermaking process comprising:providing one or more mixing apparatuses comprising a first conduithaving one or more inlets and outlets; a second conduit having one ormore inlets and outlets, wherein said first conduit secures to saidsecond conduit and traverses said second conduit; a mixing chamber thathas one or more inlets and outlets, wherein said second conduit securesto said mixing chamber and wherein said outlets of said first conduitand said outlets of said second conduit are in communication with saidmixing chamber; mounting an adaptor over an opening in a thin stock lineof said papermaking process, wherein said adaptor is in communicationwith said outlets of said mixing chamber and is secured to said mixingchamber; running said papermaking process so that said process streamflows through said thin stock line; introducing said chemicals and afeeding liquid into said mixing chamber by introducing said chemicals orfeeding liquid into said inlets of said first conduit and said secondconduit; mixing said chemicals and said feeding liquid in said mixingchamber to form a mixture of said chemicals and said feeding liquid; anddispensing said mixture into said process stream of said thin stock linethrough said adaptor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of an apparatus according to oneembodiment of the present invention.

FIG. 2 is a cross-sectional view of the apparatus of FIG. 1.

FIG. 3 is a side elevation view of the first conduit of the apparatus ofFIG. 1.

FIG. 4 is a side elevation view of the adaptor of the apparatus of FIG.1.

FIG. 5 is an exploded side elevation view of the first conduit, secondconduit, mixing chamber and adaptor of one embodiment of the presentinvention.

FIG. 6 represents a schematic illustration a method of feeding chemicalinto a process stream in accord with one embodiment of the presentinvention.

FIG. 7 represents a schematic illustration of an apparatus of thepresent invention.

FIG. 8 illustrates a schematic drawing of a headbox approach system/thinstock line.

FIG. 9 is a side elevation view of an apparatus according to oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

“Papermaking process” means a method of making paper products from pulpcomprising forming an aqueous cellulosic papermaking furnish, drainingthe furnish to form a sheet and drying the sheet. The steps of formingthe papermaking furnish, draining, and drying may be carried out in anyconventional manner generally known to those skilled in the art.

“Thin stock line” means a pipeline between a machine chest and headboxof a paper machine.

The apparatus of the present invention is essentially a reactor wherechemical reactions can either: a) happen to activate the chemicals addedto the apparatus expeditiously under controlled conditions, orb) thechemicals can be prevented from mixing with each other or other speciesby selecting appropriate mixing times versus chemical kinetics and shearlevels. For example, the reaction rate of the chemicals that are beingadded to the process stream can be slowed down or even prevented byensuring much slower chemical kinetics than the residence times insidethe device.

The number identifiers referenced throughout the DETAILED DESCRIPTION OFTHE INVENTION are noted on one or more of FIGS. 1-9; the numberidentifiers are consistent throughout all figures and therefore whenreading the DETAILED DESCRIPTION OF THE INVENTION, please reference oneor more of the nine figures.

As stated above, the apparatus of the present invention includes fourprimary components: a first conduit (1); a second conduit (4); a mixingchamber (7); and optionally an adaptor (8). The dimensions andgeometries of each element of the apparatus depends upon how muchchemical needs to be added to the papermaking process, as well otherfactors, such as the construction of the thin stock line (9). Theapparatus of the present invention may be made of any suitable materialfor handling various types of papermaking chemicals, for example,stainless steel.

The first conduit (1) has one or more inlets (2) and outlets (3).Preferably, the conduit has both a head portion (10) and a portion (11)that is conical in shape.

The second conduit (4) has one or more inlets (5) and outlets (6). Thesecond conduit (4) secures to the first conduit's head portion (10) byany fastening means that would be appreciated by one of ordinary skillin the art, for example, the head portion (10) of the first conduit andthe second conduit (4) may have one or more openings so that a screw cansecure one conduit to another.

The mixing chamber (7) has one or more inlets (17) and outlets (18) thatare in communication with the outlets of both the first conduit (1) andthe second conduit (4). The mixing chamber (7) secures to the secondconduit (4). The mixing chamber (7) may secure to the second conduit (4)by any fastening means that would be appreciated by one of ordinaryskill in the art, for example, both the second conduit (4) and themixing chamber (7) may have one or more openings so that a screw cansecure the second conduit to the mixing chamber, or the outer surface ofthe mixing chamber (7) can fuse to the outer surface of the secondconduit (4).

The adaptor (8) secures to the mixing chamber (7) and is communicationwith the outlets of the mixing chamber (7). The adaptor (8) may secureto the mixing chamber (7) by any fastening means that would beappreciated by one of ordinary skill in the art, for example, a portionof the mixing chamber (7) may insert into the adaptor (8).

In another embodiment, the inlets (5) of said second conduit (4) areperpendicular to said outlets of said second conduit (4).

In another embodiment, the first conduit (1) traverses said secondconduit (4) perpendicular to the inlets (5) of said second conduit (4).

In another embodiment, the first conduit (1) has a head portion (10)that does not traverse said second conduit (4) and a portion thattraverses said second conduit (4), wherein the portion (11) thattraverses said second conduit (4) is conical in shape and wherein thepoint of said first conduit (1) is in communication with said mixingchamber (7).

As stated above, the present invention provides for a method of feedingone or more chemicals into a process stream. In one embodiment, the (12)adaptor (8), alone or as part of the apparatuses for feeding, is mountedover an opening (16) in the thin stock line (9) and the adaptor (8) issecured to the thin stock line (9) by any means that would beappreciated by one of ordinary skill in the art. The feeding apparatusof the present invention, if not already done so, is connected with theadaptor. After this setup is established, one or more chemicals and afeeding liquid are introduced into the apparatus (12), mixed in themixing chamber (7), and fed into the thin stock line (9).

In another embodiment, the co-feeding of different chemicals into aprocess stream (13) can be achieved by the following steps: introducingseveral different chemicals into the apparatus (12), allowing a mixtureof the different chemicals to form, and dispensing the mixture into aprocess stream (13); or by aligning a series of apparatuses (12) anddispensing chemicals. Chemicals may be added to the system in any orderprescribed by a person of ordinary skill in the art. For example,chemicals maybe added sequentially, simultaneously or in pre-programmedorder.

In another embodiment, as illustrated in FIG. 8, one or more apparatuses(12) for feeding chemicals into a process stream are positionedproximate to a headbox (14) of said papermaking process. Thisorientation reduces the possibility of deactivation of the chemicalsadded to the process stream and unnecessary time delays, which hencereduces the amount of chemicals needed, and provides better control ofboth the chemicals added to the process stream and final end productproperties.

In another embodiment, the mixing is a staged mixing—mixing of chemicalsprior to their introduction into the process stream. Staged mixing lastsfor a time period that comports with the desired reaction rate of thechemicals feed into the mixing apparatus. In yet a further embodiment,the staged mixing lasts from about 5 microseconds to about 500milliseconds.

In another embodiment the activity of said chemicals is controlled byadjusting the flow rate of said chemicals and said feeding liquid, whichare introduced into said apparatuses. One or more pumps that are incommunication with said apparatuses may adjust the flow rate of thechemicals and the feeding liquid that are being introduced into theapparatus of the present invention. Staged mixing can be achieved in themixing chamber by controlling flow rates of the chemicals and thefeeding liquid into the mixing chamber.

In another embodiment, the activity of said chemicals, prior to theirintroduction into said process stream, is controlled by adjusting theflow rate of said chemicals and said feeding liquid, which areintroduced into said mixing chamber.

In another embodiment, the chemicals are selected from the groupconsisting of: biocides, strength agents, brightening agents, colors,fillers, sizing agents, retention aids, drainage aids, flocculants,washing aids, defoamers, dispersing agents, nanoparticles,microparticles, fixatives, coagulants, and a combination thereof.Various chemical treatment programs employing one or more chemicals maybe developed by one of ordinary skill in the art and employed by theapparatuses (12) of the claimed invention.

In another embodiment, the feeding liquid is selected from the groupconsisting of: fresh water; clear filtrate; whitewater; thin stock; anda combination thereof.

In another embodiment, the chemicals are diluted with a dilution liquidprior to their introduction in said first conduit (1) or said secondconduit (4). In yet a further embodiment, the dilution liquid containswater.

In another embodiment, the process stream (13) contains a furnish of apapermaking process.

In another embodiment, the process stream (13) contains a thin stock ofa papermaking process.

Referring to both FIGS. 6 and 7, in one embodiment, chemicals (19) areintroduced into the inlet (2) of a first conduit (1). Subsequently, thechemicals flow through the conduit and out said outlets (3) of the firstconduit (1) and into the inlets (17) of the mixing chamber (7). Afeeding liquid (15) is also introduced into a second conduit (4). Theliquid in the second conduit (4) swirls or vortexes around the firstconduit (1), and exits the out the outlets (6) of the second conduit andinto the mixing chamber (7) via the inlets (17) of the mixing chamber(7). The two fluids from the first conduit (1) and the second conduit(4) mix in the mixing chamber (7) and then the mixture flows through themixing chamber (7) outlet (18), which in turn flows through the adaptor(8) that is mounted to an opening (16) in the process stream (13) andthis liquid flows into the process stream (13).

1. A mixing apparatus for feeding one or more chemicals into a processstream of a papermaking process comprising: a first conduit having oneor more inlets and outlets; a second conduit having one or more inletsand outlets, wherein said first conduit secures to said second conduitand traverses said second conduit; a mixing chamber that has one or moreinlets and outlets, wherein said second conduit secures to said mixingchamber and wherein said outlets of said first conduit and said outletsof said second conduit are in communication with said mixing chamber;and an adaptor that is in communication with said outlet of said mixingchamber and is secured to said mixing chamber.
 2. The apparatus of claim1, wherein said inlets of said second conduit are perpendicular to saidoutlets of said second conduit.
 3. The apparatus of claim 1, whereinsaid first conduit has a head portion that does not traverse said secondconduit and a portion that traverses said second conduit, wherein theportion that traverses said second conduit is conical in shape andwherein the point of said first conduit is in communication with saidmixing chamber.
 4. The apparatus of claim 1, wherein said first conduitsecures to said second conduit by a fastening means.
 5. The apparatus ofclaim 1, wherein said second conduit secures to said mixing chamber by afastening means.
 6. The apparatus of claim 1, wherein said mixingchamber secures to said adaptor by a fastening means.
 7. The apparatusof claim 1, wherein said first conduit traverses said second conduit,perpendicular to the inlet of said second conduit.
 8. The apparatus ofclaim 1 wherein the apparatus is constructed and arranged to be mountedvia an adaptor over an opening in a thin stock line of a papermakingprocess such that the process stream flows through said thin stock lineof said papermaking process and that one or more chemicals and a feedingliquid may pass into said mixing chamber of said apparatuses byintroducing said chemicals or said feeding liquid into said inlets ofsaid first conduit and said second conduit of said apparatuses and saidchemicals are thereby mixed with said feeding liquid and said mixedchemicals and feeding liquid can then be dispensed into said processstream of said thin stock line through said adaptor of said apparatusesthat is in communication with said process stream.